Fire is not a solid, a liquid, a gas, or even a plasma. It is our sensory experience of a chemical reaction called combustion. Fire engages a lot of our senses at the same time, creating the kind of vivid experience we expect to come from a physical thing. Combustion creates that sensory experience using fuel, heat, and oxygen.

THIS IS COOL. I WANT TO LEARN SOMETHING ELSE, TOO!

Video via – TED-Ed
Further Readings And References @ Sparkonit, MIT, and Britannica